Nested stromal-epithelial tumor (NSET) of the liver: a case report of an extremely rare tumor

Liver Transplantation for Unresectable Calcifying Nested Stromal Epithelial Tumor: Case Report With a 1-Year Follow-Up and Review of Literature

Introduction

Calcifying nested stromal epithelial tumor (CNSET) is an extremely rare diagnosis among patients treated for primary hepatic neoplasms. There are only 45 cases reported worldwide. Histopathological characteristics are well-demarcated nests of spindle and epithelioid cells in a dense desmoplastic stroma with variable calcification and ossification. It is mostly diagnosed in children and young females. Treatment strategies implemented for the management of CNSET include radiofrequency ablation, transarterial chemoembolization, surgical resection, adjuvant and neoadjuvant chemotherapy, and liver transplantation. Given the small number of available cases, there are still no established standards of treatment for this neoplasm.

Case Presentation

A 28-year-old female diagnosed with CNSET presented mild abdominal pain, with normal laboratory values. The tumor was initially deemed unresectable, therefore, the patient was disqualified from liver resection. Further deterioration of the patient's clinical condition and local tumor progression led to qualification for liver transplantation. The patient underwent liver transplantation 1 year following initial diagnosis and a 12 months recurrence-free period was observed. During the course of treatment, she did not receive systemic chemotherapy, radiotherapy, or loco-regional treatment.

Conclusion

Multiple strategies have been implemented for the treatment of CNSET, with liver resection providing the best outcomes. Transarterial chemoembolization, radiofrequency ablation, and radiotherapy are reported to be insufficient in the management of this tumor. Various chemotherapy regimens turned out to be ineffective as well. There have been only eight reported cases of patients undergoing liver transplantation for CNSET, with tumor recurrence in two cases. CNSET appears to be a neoplasm with low malignancy potential, although an aggressive progression has subsequently been reported. Further investigation is still required in this field.

Nested Stromal-Epithelial Tumor of the Liver: A Review

BACKGROUND

Nested stromal-epithelial tumor (NSET) is a rare liver tumor, which is most commonly seen in the pediatric age group. To the best of our knowledge, there has been no published review on this rare tumor in the English literature so far.

SUMMARY

In this review, we will discuss all the reported details of the published cases, including demography, clinical presentation, molecular histogenesis, imaging, gross pathology and histopathology, immunohistochemical findings, treatment modalities, and outcome of NSET of the liver.

KEY MESSAGE

Thirty-eight cases of NSET have been reported in the last 20 years in the English literature. This tumor produces a very large and calcified mass in the liver and characteristically can present as Cushing syndrome. NSET is a nonbiliary and nonhepatocytic tumor with biphasic differentiation into 2 components of epithelial and stromal cells. The epithelial cells are arranged as nests of mildly atypical epithelial cells with a few mitotic figures. The stromal component is composed of myofibroblasts and desmoplastic stroma which often shows ossification and calcification. Immunohistochemically, this tumor is positive for both epithelial and mesenchymal markers. The majority of the reported cases in the literature had benign behavior with an indolent course.

Calcifying Nested Stromal-Epithelial Tumor of the Liver: An Update and Literature Review

Calcifying nested stromal-epithelial tumor is a rare entity that has gone by a variety of names in the literature: ossifying malignant mixed epithelial and stromal tumor, ossifying stromal-epithelial tumor, and desmoplastic nested spindle cell tumor of the liver. To our knowledge, approximately 38 cases have been reported in the literature. The histogenesis is still largely unknown but histopathologically is characterized by nests of spindle and epithelioid cells in an organoid arrangement surrounded by a prominent dense myofibroblastic stroma with occasional psammomatous calcification and focal heterotopic ossification. Vascular invasion is rare and tumoral recurrence is uncommon with only a single reported case of metastasis leading to death. Treatment is mainly by surgical intervention with the role of chemotherapy seeming limited, but lack of data hinders a true recommendation. It is important to rule out other processes such as hepatoblastoma, calcified hemangioma, synovial sarcoma, metastatic gastrointestinal stromal tumor, desmoplastic small round cell tumor, among others, which appear similar radiographically and histopathologically.

Calcifying nested stromal epithelial tumor of the liver in a patient with Klinefelter syndrome: a case report and review of the literature

BACKGROUND

Calcifying nested stromal epithelial tumor (CNSET) is a primary neoplasm of the liver, characterized by well-demarcated nests consisting of spindle and epithelioid cells with calcification and bone formation. An association of Cushing syndrome with CNSET has drawn attention, but the origin of CNSET has not been clarified.

CASE PRESENTATION

We report here the case of a 20-year-old male with Klinefelter syndrome who underwent liver resection for an increasing liver tumor that was pathologically diagnosed with CNSET. He was postoperatively followed up and received several examinations, and recurrences and extrahepatic lymph node metastases were detected on the 64th day after surgery. Chemoembolization and chemotherapy were not effective, leading to tumor progression with development of progressive liver failure, and the patient finally died 164 days after hepatectomy.

CONCLUSIONS

This case suggests that an imbalance of hormones affects the genesis and progression of CNSET, and indicates the importance of closely following patients with CNSET by imaging with attention to hepatic recurrence and extrahepatic metastases.

Are liver nested stromal epithelial tumors always low aggressive?

Nested stromal-epithelial tumor (NSET) is a non-hepatocytic and non-biliary tumor of the liver consisting of nests of epithelial and spindled cells with associated myofibroblastic stroma and variable intra-lesional calcification and ossification, which represents a very rare and challenging disease. Most of the reported cases have been treated with surgery, obtaining a long survival outcome. Here, we report the case of a 31-year-old Caucasian man who underwent surgery at our institution for a large, lobulated, multinodular mass of the right hemi-liver. The histological exam confirmed the diagnosis of NSET. After 6 mo from surgery, a liver recurrence was described and a chemo-embolization was performed. After a further disease progression, based on the correlation between the histological features of the disease and those of the hepatoblastoma, a similar chemotherapy regimen (with cisplatin and ifosfamide/mesna chemotherapy, omitting doxorubicin due to liver impairment) was administered. However, infection of the biliary catheter required a dose modification of the treatment. No benefit was noted and a progression of disease was radiologically assessed after only four cycles. The worsening of the clinical status prevented further treatments, and the patient died a few months later. This case report documents how the NSET might have an aggressive and non-preventable behavior. No chemotherapy schedules with a proved efficacy are available, and new data are needed to shed light on this rare neoplasm.

Successful liver transplantation for non-resectable desmoplastic nested spindle cell tumor complicated by Cushing's syndrome

Desmoplastic spindle cell tumors of liver are rare tumors of low malignant potential characterized by well-demarcated nests of spindle and epithelioid cells in a dense desmoplastic stroma. While surgery remains the definitive treatment, there have been reports of tumor recurrence locally and metastasis which respond poorly to chemotherapy. Hepatic transplant has been attempted in cases of recurrence or large size of primary tumor. Long-term follow-up and imaging surveillance are required as these tumors have shown a tendency for recurrence many years after initial therapy.

Nested Stromal-epithelial Tumor of Liver with Recurrent Extrahepatic Metastasis: Role of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

Nested stromal-epithelial tumor (NSET) is a very rare nonhepatocytic and nonbiliary primary tumor of the liver. An 8-year-old boy was incidentally detected with hepatic lesions, involving both lobes of the liver for which he later underwent orthotopic liver transplant. The hepatic lesions were confirmed to be NSET following histopathological examination of explant liver specimen. He later developed recurrence with multiple metastatic lesions, including multi-station nodal and right talar bone involvement. We here present the case highlighting the importance of ¹⁸F-fludeoxyglucose positron emission tomography/computed tomography in the management of this rare tumor, in particular for monitoring disease progression and/or recurrence.

Desmoplastic nested spindle cell tumours and nested stromal epithelial tumours of the liver

Desmoplastic nested spindle cell tumour of liver (DNSTL), nested stromal-epithelial tumour (NSET) and calcifying nested stromal-epithelial tumour (CNSET) are recently described entities with similar morphology, immunohistochemistry and molecular genetics. These are rare entities with only three large case series described till date. These tumours commonly present in the paediatric age group. NSETs, in addition have been described to be associated with ectopic adrenocorticotropic hormone (ACTH) production and Cushingoid features. It is important to discuss this rare group of tumours with a low malignant potential as the most common radiological differential diagnosis is hepatoblastoma, which has a relatively poorer prognosis. Thus, a pathologist needs to keep this entity in mind, so as to offer a correct histological diagnosis.

Calcifying nested stromal-epithelial tumor (CNSET) of the liver: a newly recognized entity to be considered in the radiologist's differential diagnosis

Calcifying nested stromal-epithelial tumor (CNSET), an extremely rare tumor found in the liver, was first described in 2001 by Ishak et al. The characteristic imaging features include large size, well-circumscribed, enhancing mass with calcification. To our knowledge, since 2001, there have been 29 reported. Typically arising from the right hepatic lobe, it is primarily found in children and shows clear predilection for females. Emphasizing imaging, we report a 14-year-old female with Beckwith-Wiedemann syndrome who presented with CNSET.

Nested stromal-epithelial tumour of the liver: An unusual liver entity

Nested stromal-epithelial tumours (NSETs) of the liver have been reported to be extremely unusual primary hepatic neoplasms. To date, few cases have been described in the literature. NSETs have been defined as non-hepatocytic and non-biliary tumours of the liver consisting of nests of epithelial and spindled cells, myofibroblastic stroma and variable intralesional calcification and ossification. Here, we report a case of a young female who underwent liver resection for a large hepatic lesion that proved to be a calcifying NSET on pathological examination. Details about the clinical and histopathological features of the tumour are reported.

Nested stromal epithelial tumor of the liver--liver transplantation and follow-up

BACKGROUND

The nested stromal epithelial tumor (NSET) of the liver is a rare tumor entity which is being reported in young girls.

CASE REPORT

In our 16-year-old female patient, we have performed a liver transplantation (LTX) for a non-metastasizing non-resectable liver tumor. The patient was tumor free in the follow-up. At 28 months postoperatively, we detected lung metastases in the F18-FDG-PET/CT. The patient died 37 months after LTX from progressive pulmonary metastases.

CONCLUSION

LTX should not have been generally recommended for NSET. Further statements about the value of LTX for NSET will be possible only after evaluation of the course of the disease in a larger number of transplanted patients.

Liver neoplasia in children

Management of pediatric liver tumors has significantly improved over the last 2 decades. The management options for hepatocelluar carcinoma (HCC) are not well defined. In the pediatric context, the main clinical aims are to reduce chemotherapy toxicity (predominantly ototoxicity and nephrotoxicity) in children treated for hepatoblastoma and to investigate additional modes of treatment for HCC. An increasing number of children develop HCC in the background of chronic liver disease, and screening methods need to be better observed.

Calcifying nested stroma-epithelial tumor of the liver: a case report and review of literature

Calcifying nested stromal-epithelial tumor (CNSET) of the liver is extremely rare. This tumor is characterized by nests of epithelial and spindle cells, an associated desmoplastic stroma, as well as variable calcifications and ossifications. Only 24 cases have been reported in the literature whereas none has been reported in Asian descendants. The authors report the first case of CNSET in a 34-year-old Asian woman and provide detailed histological and clinical follow-up data. Compared with those reported earlier, the present case with a history of oral contraceptive use displayed most typical features and the oldest age of onset. A retrospective study was made and the characteristics of CNSET were summarized.